-- Ported from anyfeed-server's eldenring-patch-notes.lua. That version
-- fetched each patch's own article page for its full body/description/
-- thumbnail; luafeed's method scripts only get the one page Rust already
-- fetched, with no way to fetch a second page, so this port only ever sees
-- what's on the listing page itself: title, link, and publish date (all
-- present directly on the listing card). `description` is left unset
-- rather than filled with a listing-page fragment.
--
-- site{
--   name = "eldenring-patch-notes",
--   url = "https://en.bandainamcoent.eu/elden-ring/elden-ring/news",
--   method = "eldenring-patch-notes",
--   title = "Elden Ring Patch Notes",
-- }
--
-- The page is sectioned by anchored <h2> titles ("Patch Notes (27)"), each
-- followed by a <ul class="cards-list">; the patch-notes cards link to
-- /elden-ring/news/elden-ring-patch-notes-version-<version> article pages.
-- Entries beyond the first handful load via client-side infinite scroll,
-- which a plain fetch doesn't run, so only the latest patches are ever
-- seen -- the right behavior for a feed tracker, since older patches were
-- already recorded by earlier polls. Cards are recognized by their link
-- slug rather than their position in a particular section, which survives
-- markup reshuffles.

local function origin_of(url)
	return url:match("^(https?://[^/]+)")
end

local function resolve_link(origin, href)
	if href:match("^https?://") then
		return href
	end
	return origin .. href
end

-- The stable id: the version tail of the article slug.
local function patch_id(href)
	return href and href:match("patch%-notes%-version%-(.+)$")
end

local function has_class(node, name)
	local class = node:attr("class")
	if not class then
		return false
	end
	for token in class:gmatch("%S+") do
		if token == name then
			return true
		end
	end
	return false
end

local function find_by_class(node, tag, class_name)
	local matches = {}
	for _, el in ipairs(node:find_all(tag)) do
		if has_class(el, class_name) then
			table.insert(matches, el)
		end
	end
	return matches
end

-- os.time() interprets a field table as the host's *local* time, and Lua
-- has no timezone-aware alternative in the standard library -- this
-- converts a UTC field table to the right epoch by computing the host's
-- current UTC offset and applying it, rather than assuming the host runs
-- in UTC. (Not exact across a DST transition between now and the target
-- date, an acceptable approximation for ordering feed items.)
local function utc_time(fields)
	local now = os.time()
	local isdst = os.date("*t", now).isdst
	local utc_now = os.date("!*t", now)
	utc_now.isdst = isdst
	local offset = now - os.time(utc_now)
	fields.isdst = isdst
	return os.time(fields) + offset
end

local function rfc822_midnight(date_part)
	local year, month, day = date_part:match("^(%d%d%d%d)-(%d%d)-(%d%d)$")
	if not year then
		return nil
	end
	local timestamp = utc_time({ year = tonumber(year), month = tonumber(month), day = tonumber(day), hour = 0 })
	return os.date("!%a, %d %b %Y %H:%M:%S GMT", timestamp)
end

local function build_item(origin, card, seen)
	local href = card:attr("href") or ""
	local id = patch_id(href)
	-- A duplicate card for the same patch elsewhere on the page (the latest
	-- patch also appears in the main news list) -- skip it.
	if not id or seen[id] then
		return nil
	end
	seen[id] = true

	local title_el = find_by_class(card, "h3", "card__title")[1]
	if not title_el then
		return nil
	end

	local time_el = card:find_all("time")[1]
	local date_part = time_el and (time_el:attr("datetime") or ""):match("^(%d%d%d%d%-%d%d%-%d%d)")

	return {
		title = title_el:text(),
		link = resolve_link(origin, href),
		guid = id,
		pub_date = date_part and rfc822_midnight(date_part),
	}
end

local root, url = ...
local origin = origin_of(url)
local lists = find_by_class(root, "ul", "cards-list")
local items = {}
local seen = {}
for _, list in ipairs(lists) do
	for _, card in ipairs(list:find_all("a")) do
		local item = build_item(origin, card, seen)
		if item then
			table.insert(items, item)
		end
	end
end
return items